From 5310034af2efedaec94cbf82c2c254a6c74a330f Mon Sep 17 00:00:00 2001
From: Michael Dokolin <mikhail.dokolin@elastic.co>
Date: Mon, 27 Jan 2025 21:30:22 +0100
Subject: [PATCH] [CLI] Add logging messages to simplify CPU profiling
 (#207885)

Resolves #206052.
---
 src/cli/profiler/profiler.js | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/cli/profiler/profiler.js b/src/cli/profiler/profiler.js
index ee06c0a377568..7c6b5e5b408db 100644
--- a/src/cli/profiler/profiler.js
+++ b/src/cli/profiler/profiler.js
@@ -13,16 +13,19 @@ import { join } from 'path';
 import { Session } from 'node:inspector';
 import { threadId } from 'node:worker_threads';
 import { promisify } from 'util';
+import { Logger } from '../logger';
 
 class Profiler {
   #counter = 0;
+  #logger;
   #path;
   #session;
 
-  constructor() {
+  constructor(logger) {
     const execOpts = getopts(process.execArgv);
     const envOpts = getopts(process.env.NODE_OPTIONS ? process.env.NODE_OPTIONS.split(/\s+/) : []);
     this.#path = execOpts['diagnostic-dir'] || envOpts['diagnostic-dir'] || process.cwd();
+    this.#logger = logger;
   }
 
   #getPath() {
@@ -51,13 +54,17 @@ class Profiler {
 
     await promisify(this.#session.post)('Profiler.enable');
     await promisify(this.#session.post)('Profiler.start');
+    this.#logger.log(`CPU profiling is started for process '${process.pid}'.`);
   }
 
   async #stop() {
     try {
       const { profile } = await promisify(this.#session.post)('Profiler.stop');
+      this.#logger.log(`CPU profiling is stopped for process '${process.pid}'.`);
+
       const path = this.#getPath();
       await promisify(writeFile)(path, JSON.stringify(profile));
+      this.#logger.log(`Saved CPU profile to '${path}'.`);
     } finally {
       this.#session.disconnect();
       this.#session = undefined;
@@ -81,8 +88,10 @@ export default function (program) {
         return;
       }
 
-      const profiler = new Profiler();
+      const logger = new Logger();
+      const profiler = new Profiler(logger);
       process.removeAllListeners(signal);
       process.on(signal, profiler.toggle.bind(profiler));
+      logger.log(`CPU profiling is enabled on '${signal}' for process '${process.pid}'.`);
     });
 }